1. Field of the Invention
The present invention is related to the creation, maintenance and use of computerized expert systems, and, more particularly, to a method for creating and maintaining an expert system rulebase for use with different pieces of equipment of the same type.
2. Description of the Related Art
There is currently an increasing use of expert systems for evaluating equipment, particularly during operation. With many types of equipment, such as electrical generators used by power companies and other types of equipment of similar size, there are several pieces of equipment of a single type or model which are constructed to be virtually identical. However, due to differences in the construction process or the environment in which pieces of equipment are operated, there are variations in the values of certain parameters or sensor readings for a type of equipment which are consistent for a specific unit. Such characteristics are conventionally expressed as, e.g., "it tends to run hot" or "this one's a little slow to warm up", etc.
Existing expert systems typically allow for such variations between units by maintaining a single rulebase for each piece of equipment. If it is discovered that a change should be made to the rulebases for all pieces of equipment of a certain type, each rulebase must be changed individually. The change cannot be made once and copied to the other rulebases, because then the properties unique to a specific piece of equipment would be overwritten by properties in the rulebase which was first modified. Some expert systems may attempt to alleviate such problems by segregating properties into one file defining rules and another file defining parameters. This would allow changes to the rules to be copied from one rulebase to another without affecting the parameters, but does not allow for rules to be unique to a specific piece of equipment or for a change to the parameter file to be made in common to all pieces of equipment of a specific type.